Consecutive Occupational Heat Exposure With and Without Overnight Cooling

June 14, 2026 updated by: Glen P. Kenny, University of Ottawa

Physiological Responses to Consecutive Days of Occupational Heat Exposure With and Without Overnight Access to Cooling

Extreme heat events are becoming more frequent, intense, and prolonged, increasing the risk of heat-related illness among workers exposed to hot environments. Current occupational heat-stress guidelines are designed to limit excessive increases in core body temperature and physiological strain during work in the heat through the use of work-rest schedules. However, these guidelines are largely based on single-day heat exposures and assume that workers recover in cool indoor environments between shifts. During heat events, many workers may instead recover in homes or accommodations that remain overheated, particularly in the absence of air conditioning. Inadequate overnight cooling may impair the body's ability to dissipate heat, increase physiological strain, and reduce tolerance to heat exposure on subsequent workdays. Older adults may be especially vulnerable due to age-related impairments in heat-loss capacity. To date, the effects of recovering in an overheated indoor environment on physiological strain and thermoregulatory function during repeated occupational heat exposure remain poorly understood, limiting the development of evidence-based recommendations to protect workers during prolonged heat events.

The primary objective of this study is to determine whether overnight recovery in an overheated indoor environment increases physiological strain during repeated occupational heat exposure in older adults. Specifically, investigators will assess whether recovery at the recently proposed upper indoor temperature limit of 26°C and 45% relative humidity (RH) (PMID: 38329752) is sufficient to attenuate elevations in core temperature during subsequent work in the heat compared with recovery in an overheated indoor environment (31°C, 45% RH) representative of conditions commonly experienced during extreme heat events. Healthy older adults will complete two consecutive days and nights of simulated moderate-intensity occupational heat exposure, with overnight recovery occurring in either the 26°C or 31°C condition. Measures of core temperature, cardiovascular strain, heat-loss capacity, hydration status, sleep quality, cognitive function, mood, and perceptual responses will be assessed to determine the impact of overnight recovery conditions on responses to repeated heat exposure. Whole-body heat-loss capacity will also be evaluated before and after the exposure protocol as assessed during incremental, intermittent exercise protocol performed in an air calorimeter.

Study Overview

Study Type

Interventional

Enrollment (Estimated)

10

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

    • Ontario
      • Ottawa, Ontario, Canada, K1N 6N5
        • University of Ottawa

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Are male.
  • Do not smoke or have been smoke free for at least 5 years.
  • English or French speaking.
  • Ability to provide informed consent.
  • Are physically active (engage in exercise at least 2 times per week for ≥30 minutes)

Exclusion Criteria:

  • Are regularly exposed to hot environments (e.g., occupational heat exposure)
  • Experience claustrophobia or discomfort in enclosed environments
  • Episode(s) of severe hypoglycemia (requiring the assistance of another person) within the previous year, or inability to sense hypoglycemia (hypoglycemia unawareness).
  • Serious complications related to diabetes (gastroparesis, renal disease, uncontrolled hypertension, severe autonomic neuropathy).
  • Uncontrolled hypertension - BP >150 mmHg systolic or >95 mmHg diastolic in a sitting position.
  • Restrictions in physical activity due to disease (e.g. intermittent claudication, renal impairment, active proliferative retinopathy, unstable cardiac or pulmonary disease, disabling stroke, severe arthritis, etc.).
  • Use of or changes in medication judged by the patient or investigators to make participation in this study inadvisable.
  • Cardiac abnormalities identified during screening

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Recovery at recommended indoor temperature limit
Participants complete a 2-day, 2-night simulated occupational heat exposure protocol consisting of daytime work in a hot environment (37.5°C, 35% RH) and overnight recovery (18:30-08:00) at the recommended upper indoor temperature limit (26°C, 45% RH).
Participants complete a 2-day, 2-night simulated occupational heat exposure protocol involving daytime work in a hot environment (37.5°C, 35% RH) and overnight recovery (18:30-08:00) at the recommended upper indoor temperature limit (26°C, 45% RH).
Experimental: Recovery in an overheated indoor environment
Participants complete a 2-day, 2-night simulated occupational heat exposure protocol consisting of daytime work in a hot environment (37.5°C, 35% RH) and overnight recovery (18:30-08:00) in an overheated indoor environment (31°C, 45% RH).
Participants complete a 2-day, 2-night simulated occupational heat exposure protocol involving daytime work in a hot environment (37.5°C, 35% RH) and overnight recovery (18:30-08:00) in an overheated indoor environment (31°C, 45% RH).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Total work volume.
Time Frame: During each 240-minute morning and afternoon work bout on Day 1 and Day 2.
Total work completed during the 240-minute work protocol performed in the morning and afternoon work periods, expressed as cumulative minutes of work performed over the two consecutive work days. The work period consists of an initial continuous walking phase to a core temperature 38.0°C or 1°C increase above baseline resting (as measured prior to the start of the 2-day work protocol), followed by intermittent work-rest cycles. The morning and afternoon work periods are separated by a 1-hour recovery period.
During each 240-minute morning and afternoon work bout on Day 1 and Day 2.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Time to core temperature of 38.0°C
Time Frame: During each 240-minute morning and afternoon work bout on Day 1 and Day 2.
Time, in minutes, from the start of continuous walking to the point at which core temperature reaches 38.0°C. Participants who do not reach 38.0°C before voluntary termination, reaching the applicable stopping criterion, or completing 240 minutes of continuous walking will have their time recorded at termination or completion.
During each 240-minute morning and afternoon work bout on Day 1 and Day 2.
Time to 1.0°C increase in rectal temperature
Time Frame: During each 240-minute morning and afternoon work bout on Day 1 and Day 2.
Time, in minutes, from the start of continuous walking to the point at which rectal temperature increases by 1.0°C above baseline. For participant safety, continuous walking will not continue beyond a rectal temperature of 38.5°C. Therefore, for participants who reach 38.5°C before attaining a 1.0°C increase in rectal temperature, the time at which 38.5°C is reached will be recorded. Participants who voluntarily terminate exercise or complete 240 minutes of continuous walking before reaching either endpoint will have their time recorded at termination or completion.
During each 240-minute morning and afternoon work bout on Day 1 and Day 2.
Average core temperature during work/rest cycles
Time Frame: During each 240-minute morning and afternoon work bout on Day 1 and Day 2.
Average core temperature measured during the intermittent work-rest cycles following the initial continuous work period.
During each 240-minute morning and afternoon work bout on Day 1 and Day 2.
Heart rate at core temperature of 38.0°C
Time Frame: Each morning and afternoon work bout on Day 1 and Day 2.
Heart rate measured at the time a participant reaches a rectal temperature of 38.0°C during the initial continuous walking period. For participants who do not reach a rectal temperature of 38.0°C before voluntary termination, reaching the applicable stopping criterion, or completing 240 minutes of continuous walking, heart rate at termination or completion will be recorded.
Each morning and afternoon work bout on Day 1 and Day 2.
Heart rate at 1.0°C increase in core temperature
Time Frame: Each morning and afternoon work bout on Day 1 and Day 2.
Heart rate measured at the time a participant achieves a 1.0°C increase in core temperature above baseline during the initial continuous walking period. For participant safety, continuous walking will not continue beyond a core temperature of 38.5°C. Therefore, for participants who reach a core temperature of 38.5°C before attaining a 1.0°C increase above baseline, the heart rate at 38.5°C will be recorded. Participants who voluntarily terminate exercise or complete 240 minutes of continuous walking before reaching either endpoint will have their final recorded heart rate used.
Each morning and afternoon work bout on Day 1 and Day 2.
Average heart rate during work/rest cycles
Time Frame: During each 240-minute morning and afternoon work bout on Day 1 and Day 2.
Average heart rate measured during the intermittent work-rest cycles following the initial continuous work period.
During each 240-minute morning and afternoon work bout on Day 1 and Day 2.
Mean skin temperature at core temperature of 38.0°C
Time Frame: Each morning and afternoon work bout on Day 1 and Day 2.
Mean skin temperature measured at the time a participant reaches a core temperature of 38.0°C during the initial continuous walking period. For participants who do not reach a core temperature of 38.0°C before voluntary termination, reaching the applicable stopping criterion, or completing 240 minutes of continuous walking, mean skin temperature at termination or completion will be recorded.
Each morning and afternoon work bout on Day 1 and Day 2.
Mean skin temperature at 1.0°C increase in core temperature
Time Frame: Each morning and afternoon work bout on Day 1 and Day 2.
Mean skin temperature measured at the time a participant achieves a 1.0°C increase in core temperature above baseline during the initial continuous walking period. For participant safety, continuous walking will not continue beyond a core temperature of 38.5°C. Therefore, for participants who reach a core temperature of 38.5°C before attaining a 1.0°C increase above baseline, the mean skin temperature at 38.5°C will be recorded. Participants who voluntarily terminate exercise or complete 240 minutes of continuous walking before reaching either endpoint will have their final recorded mean skin temperature used.
Each morning and afternoon work bout on Day 1 and Day 2.
Average mean skin temperature during work/rest cycles
Time Frame: During each 240-minute morning and afternoon work bout on Day 1 and Day 2.
Average mean skin temperature measured during the intermittent work-rest cycles following the initial continuous work period.
During each 240-minute morning and afternoon work bout on Day 1 and Day 2.
Overnight heart rate
Time Frame: Overnight recovery periods (18:30-08:00) on Night 1 and Night 2.
Average heart rate during the overnight recovery period. Heart rate will be measured continuously throughout each overnight exposure.
Overnight recovery periods (18:30-08:00) on Night 1 and Night 2.
Overnight mean skin temperature
Time Frame: Overnight recovery periods (18:30-08:00) on Night 1 and Night 2.
Average mean skin temperature during the overnight recovery period. Mean skin temperature will be measured continuously throughout each overnight exposure.
Overnight recovery periods (18:30-08:00) on Night 1 and Night 2.
Overnight core temperature
Time Frame: Overnight recovery periods (18:30-08:00) on Night 1 and Night 2.
Average core temperature during the overnight recovery period. Core temperature will be measured continuously throughout each overnight exposure.
Overnight recovery periods (18:30-08:00) on Night 1 and Night 2.
Metabolic workload
Time Frame: During morning and afternoon work bouts on Day 1 and Day 2.
Metabolic workload during simulated occupational work will be assessed using indirect calorimetry. Oxygen consumption (VO₂) and respiratory exchange ratio (RER) will be measured and used to calculate metabolic workload, expressed in watts per square meter (W/m²). Higher values indicate greater metabolic heat production and physiological work demand.
During morning and afternoon work bouts on Day 1 and Day 2.
Whole-body evaporative heat loss
Time Frame: Baseline approximately 7 days before exposure and post-exposure on the morning of Day 3.
Change in whole-body evaporative heat loss from baseline to post-exposure, assessed using direct air calorimetry during standardized exercise at three work intensities.
Baseline approximately 7 days before exposure and post-exposure on the morning of Day 3.
Whole-body dry heat exchange
Time Frame: Baseline approximately 7 days before exposure and post-exposure on the morning of Day 3.
Change in whole-body dry heat exchange from baseline to post-exposure, assessed using direct air calorimetry during standardized exercise at three work intensities.
Baseline approximately 7 days before exposure and post-exposure on the morning of Day 3.
Whole-body total heat loss
Time Frame: Baseline approximately 7 days before exposure and post-exposure on the morning of Day 3.
Change in whole-body total heat loss from baseline to post-exposure, assessed using direct air calorimetry during standardized exercise at three work intensities.
Baseline approximately 7 days before exposure and post-exposure on the morning of Day 3.
Urine specific gravity
Time Frame: Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Urine specific gravity will be measured to assess hydration status. Higher values indicate greater urine concentration and therefore poorer hydration status, whereas lower values indicate lower urine concentration and therefore better hydration status.
Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Fluid loss from body mass change
Time Frame: Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Fluid loss calculated from changes in body mass during each daytime work exposure, corrected for food and fluid intake.
Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Changes in plasma volume
Time Frame: Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Change in plasma volume from baseline values calculated from duplicate measurements of hemoglobin and hematocrit at the start and end of each exposure using the technique by Dill and Costill
Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Systolic blood pressure
Time Frame: Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Systolic blood pressure measured in triplicate using automated oscillometry.
Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Diastolic blood pressure
Time Frame: Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Diastolic blood pressure measured in triplicate using automated oscillometry.
Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Orthostatic intolerance symptoms
Time Frame: Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Cumulative sum of scores on 6 questions asking participant to rank symptoms associated with orthostatic intolerance. All symptoms scored on a scale from 0 (none) to 10 (worst possible) and include feelings of: (1) "dizziness, lightheadedness, feeling faint, or feeling like you might black out"; (2) "Problems with vision (blurring, seeing spots, tunnel vision, etc.)"; (3) "Weakness"; (4) "Fatigue"; (5) "Trouble concentrating"; and (6) "Head and neck discomfort"
Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Thermal sensation scale
Time Frame: Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Thermal sensation will be assessed using a visual analog ASHRAE-based scale in response to the question "How hot do you feel?" Scores range from 0 (neutral) to 7 (extremely hot). Higher scores indicate a greater sensation of heat and therefore a worse outcome, whereas lower scores indicate less perceived heat and therefore a better outcome.
Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Thermal comfort
Time Frame: Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Thermal comfort will be assessed in response to the question "How comfortable does your body temperature feel?" using a visual analog scale ranging from 1 (comfortable) to 4 (very uncomfortable). Higher scores indicate lower thermal comfort and therefore a worse outcome, whereas lower scores indicate greater thermal comfort and therefore a better outcome.
Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Thirst sensation
Time Frame: Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Thirst sensation will be assessed in response to the question "How thirsty are you?" using a visual analog scale ranging from 1 (not thirsty at all) to 9 (very, very thirsty). Higher scores indicate greater thirst and therefore a worse outcome, whereas lower scores indicate less thirst and therefore a better outcome.
Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Rating of Perceived Exertion (Borg 6-20 Scale)
Time Frame: Each morning and afternoon work bout on Day 1 and Day 2.
Perceived exertion will be assessed using a visual analog scale in response to the question "How hard are you working?" Scores range from 6 (no exertion at all) to 20 (maximal exertion). Higher scores indicate greater perceived effort and therefore a worse outcome, whereas lower scores indicate less perceived effort and therefore a better outcome.
Each morning and afternoon work bout on Day 1 and Day 2.
Feel-good scale
Time Frame: Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Feelings of well-being will be assessed using a visual analog scale in response to the question "How good do you feel?" Scores range from -5 (very bad) to +5 (very good), with 0 representing neutral. Higher scores indicate more positive feelings and therefore a better outcome, whereas lower scores indicate more negative feelings and therefore a worse outcome.
Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Sleep duration
Time Frame: Assessed on the morning of Day 1, Day 2, and Day 3
Sleep quantity will be assessed each morning using a sleep diary. Participants will report their bedtime, wake time, and total sleep duration during the previous night. Sleep duration will be recorded in hours, with higher values indicating longer sleep duration.
Assessed on the morning of Day 1, Day 2, and Day 3
Sleep quality rating
Time Frame: Assessed on the morning of Day 1, Day 2, and Day 3
Sleep quality will be assessed each morning using a sleep diary. Participants will rate the quality of their sleep during the previous night on a 5-point scale ranging from 1 (very poor) to 5 (very good). Higher scores indicate better perceived sleep quality, whereas lower scores indicate poorer perceived sleep quality.
Assessed on the morning of Day 1, Day 2, and Day 3
Overnight thermal symptom score
Time Frame: Assessed on the morning of Day 1, Day 2, and Day 3
Thermal symptoms experienced during sleep will be assessed each morning using the Sleep Sensation Questionnaire. Participants will rate the severity of heat- and sweat-related symptoms experienced overnight, including feeling too hot, feeling sweaty, and sweat accumulation on bedding. Responses range from 0 (not at all) to 4 (extremely) for each symptom and are summed to generate a total symptom score. Total scores range from 0 to 32, with higher scores indicating greater overnight thermal discomfort.
Assessed on the morning of Day 1, Day 2, and Day 3
Profiles of Mood States (POMS-40) total mood disturbance score
Time Frame: Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Mood state will be assessed using the 40-item Profiles of Mood States (POMS-40) questionnaire. Participants will rate how they feel at the time of assessment using a 5-point Likert scale ranging from 0 (not at all) to 4 (extremely). Responses will be summed to generate a total score. Higher scores indicate greater overall mood disturbance and therefore a worse outcome, whereas lower scores indicate lower mood disturbance and therefore a better outcome.
Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Environmental Symptoms Questionnaire-IV (ESQ-IV) total symptom score
Time Frame: Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Environmental symptomatology associated with prolonged heat exposure will be assessed using the Environmental Symptoms Questionnaire-IV (ESQ-IV). Participants will rate 68 symptoms using a 6-point Likert scale ranging from 0 (not at all) to 5 (extreme). Responses are summed, with positive items reverse scored as appropriate, to generate a Total Symptom Score ranging from 0 to 340. Higher scores indicate greater symptom burden and therefore a worse outcome, whereas lower scores indicate fewer symptoms and therefore a better outcome.
Assessed at baseline and throughout Day 1, Day 2, and Day 3.
State hostility scale total score
Time Frame: Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Hostility and aggression will be assessed using the State Hostility Scale, a self-report questionnaire evaluating feelings of hostility, irritability, anger, and aggressive affect. Responses are summed to generate a total score after reverse scoring of applicable items. Total scores range from 35 to 175, with higher scores indicating greater hostility and aggression and therefore a worse outcome, whereas lower scores indicate less hostility and aggression and therefore a better outcome.
Assessed at baseline and throughout Day 1, Day 2, and Day 3.
Cued Stroop Test average reaction time (Sway Medical)
Time Frame: Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Executive function will be assessed using the Cued Stroop Test administered through the Sway Medical platform. Participants will complete a series of congruent, neutral, and incongruent color-word tasks requiring response inhibition and cognitive flexibility. Performance will be quantified using average reaction time, measured in milliseconds (ms). Lower values indicate faster responses and therefore better executive function, whereas higher values indicate slower responses and therefore poorer executive function.
Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Cued Stroop Test error count (Sway Medical)
Time Frame: Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Executive function will be assessed using the Cued Stroop Test administered through the Sway Medical platform. Participants will complete a series of congruent, neutral, and incongruent color-word tasks requiring response inhibition and cognitive flexibility. Performance will be quantified using the total number of errors recorded during the test. Lower values indicate better executive function, whereas higher values indicate poorer executive function.
Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Impulse Control Test reaction time (Sway Medical)
Time Frame: Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Participants will be provided with a tablet device running the Sway Medical testing platform for the assessment of impulse control. During the Impulse Control Test, participants will be presented with a series of visual "go" and "no-go" cues. Participants will be instructed to initiate a movement of the device as quickly as possible in response to "go" cues and to withhold movement in response to "no-go" cues. Performance will be quantified using reaction time, measured in milliseconds (ms). Lower values indicate faster responses and therefore better impulse control, whereas higher values indicate slower responses and therefore poorer impulse control.
Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Impulse Control Test error count (Sway Medical)
Time Frame: Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Participants will be provided with a tablet device running the Sway Medical testing platform for the assessment of impulse control. During the Impulse Control Test, participants will be presented with a series of visual "go" and "no-go" cues. Participants will be instructed to initiate a movement of the device as quickly as possible in response to "go" cues and to withhold movement in response to "no-go" cues. Performance will be quantified using the total number of errors recorded during the test, including failures to respond appropriately to the presented cue. Lower values indicate better impulse control, whereas higher values indicate poorer impulse control.
Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Reaction Time Test reaction time (Sway Medical)
Time Frame: Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Participants will be provided with a tablet device running the Sway Medical testing platform for the assessment of reaction time. During the Reaction Time Test, participants will be presented with a visual cue and instructed to initiate a movement of the device as quickly as possible in response. Performance will be quantified using reaction time, measured in milliseconds (ms). Lower values indicate faster responses and therefore better reaction time performance, whereas higher values indicate slower responses and therefore poorer reaction time performance.
Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Memory Test working memory score (Sway Medical)
Time Frame: Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Memory will be assessed using the Memory Test administered through the Sway Medical platform. Participants will be presented with a three-letter code to memorize, followed by a series of increasingly complex spatial memory tasks involving the recall of patterns displayed on a 2 × 3 grid. Performance will be quantified using the Working Memory Score, defined as the number of spatial patterns correctly recalled before an error is made. Higher scores indicate better working memory performance, whereas lower scores indicate poorer working memory performance.
Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Memory Test delayed recall score (Sway Medical)
Time Frame: Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Memory will be assessed using the Memory Test administered through the Sway Medical platform. Participants will be presented with a three-letter code to memorize, followed by a series of increasingly complex spatial memory tasks involving the recall of patterns displayed on a 2 × 3 grid. Following completion of the spatial memory task, participants will be asked to recall the original three-letter code. Performance will be quantified using the Delayed Recall Score, which ranges from 0 to 3 and reflects the number of letters correctly recalled. Higher scores indicate better delayed recall performance, whereas lower scores indicate poorer delayed recall performance.
Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
CDC 4-Stage Balance Test composite score (Sway Medical)
Time Frame: Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Balance will be assessed using the CDC 4-Stage Balance Test administered through the Sway Medical platform. Participants will hold a tablet device against their chest while auditory cues guide them through four consecutive stances: feet side-by-side, semi-tandem stance, tandem stance, and single-leg stance. Body sway will be measured using the tablet's integrated accelerometer and quantified using a composite balance score generated by the Sway Medical platform. Scores range from 0 to 100, with higher scores indicating better balance performance and lower scores indicating poorer balance performance.
Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Postural sway total path excursion length (BTrackS Force Plate)
Time Frame: Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Balance will be assessed using a BTrackS force plate. Participants will stand with their feet shoulder-width apart, hands on their hips, and eyes closed. The assessment will consist of four 20-second trials, including one practice trial, separated by 20 seconds of rest. Center of pressure (COP) displacement along the mediolateral (x) and anteroposterior (y) axes will be used to calculate total path excursion length, measured in centimeters (cm). Lower values indicate less postural sway and therefore better balance performance, whereas higher values indicate greater postural sway and therefore poorer balance performance.
Each morning and evening on Day 1 and Day 2, as well as the morning of Day 3.
Heart rate variability: standard deviation of normal R-R intervals (SDNN)
Time Frame: Throughout Day 1, Day 2, and Day 3.
Cardiac autonomic modulation will be assessed using a 5-lead Holter electrocardiogram (ECG) monitor (DigiTrak XT, Philips Zymed, Andover, MA, USA). Consecutive R-R intervals will be derived from the ECG recording to calculate the standard deviation of normal R-R intervals (SDNN), measured in milliseconds (ms). Higher values indicate greater heart rate variability and cardiac autonomic modulation, whereas lower values indicate reduced heart rate variability and cardiac autonomic modulation.
Throughout Day 1, Day 2, and Day 3.
Heart rate variability: root mean square of successive differences (RMSSD)
Time Frame: Throughout Day 1, Day 2, and Day 3.
Cardiac autonomic modulation will be assessed using a 5-lead Holter electrocardiogram (ECG) monitor (DigiTrak XT, Philips Zymed, Andover, MA, USA). Consecutive R-R intervals will be derived from the ECG recording to calculate the root mean square of successive differences between adjacent normal R-R intervals (RMSSD), measured in milliseconds (ms). Higher values indicate greater parasympathetic modulation and heart rate variability, whereas lower values indicate reduced parasympathetic modulation and heart rate variability.
Throughout Day 1, Day 2, and Day 3.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Publications and helpful links

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Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

July 1, 2026

Primary Completion (Estimated)

June 30, 2027

Study Completion (Estimated)

August 31, 2027

Study Registration Dates

First Submitted

June 9, 2026

First Submitted That Met QC Criteria

June 14, 2026

First Posted (Actual)

June 18, 2026

Study Record Updates

Last Update Posted (Actual)

June 18, 2026

Last Update Submitted That Met QC Criteria

June 14, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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